y=cos3次方x求导数啊_数学解答

y=cos3次方x求导数啊

人气：119 ℃　时间：2019-09-20 09:57:54

解答

{cos^3 (3x)}'
= 3 cos^2(3X) {cos(3x)}'
= 3 cos^2(3X) {-sin(3x)} (3x)'
= 3 cos^2(3X) {-sin(3x)} 3
= -9 sin(3x) cos^2(3x)